A Simplified Model for Particle Internal Temperature Calculation in Fluidized Bed

Abstract

Thermal mechanism analysis of heat exchange between a gas phase flow and the internal region of a particulate is still a subject of interest among researchers, mainly due to its complexity and lack of a simplified (in terms of computational effort) solution. Main goal of present work is to develop a simplified model capable of predict internal particle temperature, as a function of its surface temperature and flow conditions, in a fluidized bed, transporting spherical particles. Proposed model was implemented in C++ programming language and an algorithm was developed to solve two energy equations, for gas and particulate phases, and an algebraic equation to determine internal particle temperature. As a result, predicted particle temperature decreases while gas temperature rises. At approximate 12 m, both temperatures reach the equilibrium at 755 K which remains unaltered up to the riser outlet section. Energy balance verification, between inlet and outlet riser sections, showed that proposed model and balance calculated temperatures agree with a difference of 1.804E−11 kW on the outlet. In terms of internal particle temperature, results showed that it remains higher than surface temperature from riser entrance up to approximated 32.8 m. After this point it reaches surface temperature, which already is in equilibrium with the gas phase temperature.